I have only one short piece of commentary to add to this, but I'm a big enough baseball geek to just stare at this chart and think about the possibilities:
Here's the one piece of commentary I'd like to offer: How far does the current trend in run scoring go? NL run scoring (the better barometer, since the DH changed AL run scoring substantially) is pointed in the direction toward the Deadball Era. Will it keep going and bottom out that low? We'll see. Personally, I think it will if MLB doesn't change the rules.